trap speed vs whp
08-02-2012, 01:45 AM
#28
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Re: trap speed vs whp
I kind of have to agree with FWD turbo cars don't fit into the on line calculators. Last weekend the Top dragster cars were running 190mph and 6.90. We all know Speedfactory just went 190mph.
08-02-2012, 05:05 AM
#29
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Re: trap speed vs whp
Is there a big difference between NASP and FI when you compare BHP and torque?
See NASP set-ups running into the 10's with lower power and MPH than the equivalent time run by FI.
See NASP set-ups running into the 10's with lower power and MPH than the equivalent time run by FI.
08-02-2012, 05:09 AM
#30
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Re: trap speed vs whp
Far from an expert, but the Short times (60 foot) of those old V8's kills our FWD 60's. I mean those guys are cutting 1.3 60 foots.
08-02-2012, 06:03 AM
#31
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Re: trap speed vs whp
Too many variables from one car to another. Torque can make a huge difference also, some people will make 50-75 wtq less/more than others at the same hp levels. Then you have gearing that will make a big difference, even how much you can rev the car and carry the power plays a huge factor. Not even mentioning aerodynamics of the car, then throw in weight. I've seen cars with 600whp+ running the same times as cars running 300whp before. Then the biggest factor of them all.... the driver...
Take our car for instance:
Engine- KMOD K24 Turbo(6266 T3)
Weight- 2700lbs
Power- 726whp
Torque- 487wtq
Gearing- Very short(in 5th gear @ 9800rpm going thru the traps)
Tire- 24.5x8.5x15 M&H
Et- 10.20
MPH- 150mph
I've seen plenty of much lighter cars w/ better power to weight ratios that trap 10-15mph less than our car. According to calculators(math) those other cars should be trapping higher mph's than we are.
Video-http://www.youtube.com/playlist?list...ature=view_all
-Marquis
-KMOD
08-02-2012, 06:40 AM
#32
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Re: trap speed vs whp
agreed. it was the result of a dog **** track.
same car and setup would go a few tenths faster with 2-4 more mph when i would drive down to englishtown. it happened every time with all my setups for many years. yay lebanon valley
08-03-2012, 10:53 AM
#33
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Re: trap speed vs whp
This is very true. But for what it is, it's a good track.
08-03-2012, 01:19 PM
#34
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Re: trap speed vs whp
yeah you're right. pretty low key and it has gotten better recently. as much as i hate on it, i do go there more than any other track
11-13-2012, 02:05 AM
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Re: trap speed vs whp
Too many variables from one car to another. Torque can make a huge difference also, some people will make 50-75 wtq less/more than others at the same hp levels. Then you have gearing that will make a big difference, even how much you can rev the car and carry the power plays a huge factor. Not even mentioning aerodynamics of the car, then throw in weight. I've seen cars with 600whp+ running the same times as cars running 300whp before. Then the biggest factor of them all.... the driver...
if a dyno claims less "wtq" than another car even though the whp are the same. its 99.9% safe to assume its just because of the rpm range. a deisel, and a honda could both put out 300whp. but since the deisel revs so low, in order to produce 300whp, it made have 600lbs of tq at the crank, resulting in a "500wtq" number while the honda gets its "200wtq". Both had the same amount of energy at the wheel at the same rpm output, but the rpm's were greatly different at the crank. wtq is NOT a symbol of power. wtq numbers actually make no bit of difference. for i could drop compression, and add a cam. sets say that results in the samepeak tq number, but now its at a higher rpm range. so i would gain whp, while keeping the "wtq" the same. whp is all that matters...just saying
11-13-2012, 06:21 AM
#36
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Re: trap speed vs whp
Well, judging by the little chart that was posted, my hp guess for my car was right. Turbo D EF, 2klbs with driver ran 107mph. I was expecting about 270whp from my street tune. Time for more boost.
11-13-2012, 06:22 AM
#37
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Re: trap speed vs whp
when a dyno spits out a "wtq" number, what the dyno is attempting to do is calculate crank tq - tranny loss. if the car made 300 crank tq and after the energy loss from tranny, it puts down 243lbs of tq. its not actual WHEEL tq. for in 1st gear, the wheel tq output would be roughly 16 times greater than the crank tq. so a stock honda producing 140lbs of tq at the crank will see roughly (140x16)x .82 (18% loss) = 1900lbs of tq at the wheel.
if a dyno claims less "wtq" than another car even though the whp are the same. its 99.9% safe to assume its just because of the rpm range. a deisel, and a honda could both put out 300whp. but since the deisel revs so low, in order to produce 300whp, it made have 600lbs of tq at the crank, resulting in a "500wtq" number while the honda gets its "200wtq". Both had the same amount of energy at the wheel at the same rpm output, but the rpm's were greatly different at the crank. wtq is NOT a symbol of power. wtq numbers actually make no bit of difference. for i could drop compression, and add a cam. sets say that results in the samepeak tq number, but now its at a higher rpm range. so i would gain whp, while keeping the "wtq" the same. whp is all that matters...just saying
if a dyno claims less "wtq" than another car even though the whp are the same. its 99.9% safe to assume its just because of the rpm range. a deisel, and a honda could both put out 300whp. but since the deisel revs so low, in order to produce 300whp, it made have 600lbs of tq at the crank, resulting in a "500wtq" number while the honda gets its "200wtq". Both had the same amount of energy at the wheel at the same rpm output, but the rpm's were greatly different at the crank. wtq is NOT a symbol of power. wtq numbers actually make no bit of difference. for i could drop compression, and add a cam. sets say that results in the samepeak tq number, but now its at a higher rpm range. so i would gain whp, while keeping the "wtq" the same. whp is all that matters...just saying
Also, chassis dyno's have absolutely no way of determing "engine" torque. They are not guessing at an efficiency rating. They are not picking a number out of their *** either. They are measuring the acceleration of the drum and deriving power directly, and using the RPM and speed of the drum to derive the torque required as well.
Also, in case you are not aware, ftlb/s is the units of horsepower. In other words, horsepower is the rate at which torque is being applied. (which is why if you can carry your torque high into the RPM ranges, you will make loads of horsepower)
Don't be silly, torque is everything to going down the track faster. Understanding where and how you want to apply is what makes the difference.
11-13-2012, 06:46 AM
#38
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Re: trap speed vs whp
"wtq" is referred to as "base" torque. It is then multiplied by your gear ratio to achieve effective torque.
Also, chassis dyno's have absolutely no way of determing "engine" torque. They are not guessing at an efficiency rating. They are not picking a number out of their *** either. They are measuring the acceleration of the drum and deriving power directly, and using the RPM and speed of the drum to derive the torque required as well.
Also, in case you are not aware, ftlb/s is the units of horsepower. In other words, horsepower is the rate at which torque is being applied. (which is why if you can carry your torque high into the RPM ranges, you will make loads of horsepower)
Don't be silly, torque is everything to going down the track faster. Understanding where and how you want to apply is what makes the difference.
Also, chassis dyno's have absolutely no way of determing "engine" torque. They are not guessing at an efficiency rating. They are not picking a number out of their *** either. They are measuring the acceleration of the drum and deriving power directly, and using the RPM and speed of the drum to derive the torque required as well.
Also, in case you are not aware, ftlb/s is the units of horsepower. In other words, horsepower is the rate at which torque is being applied. (which is why if you can carry your torque high into the RPM ranges, you will make loads of horsepower)
Don't be silly, torque is everything to going down the track faster. Understanding where and how you want to apply is what makes the difference.
a dyno can estimate crank tq by knowing the wheel tq at a certain rpm whp). knowing hp, and what rpm it was achieved, it can derive what the tq at the crank is ( this number reflects losses). this we agreed on.
I understand hp and tq completely. I was simply stating that "wheel tq" that dyno's give out is a 100% useless term in regards of figuring out how fast the car will be.
Base tq is what they are referring to as "wtq" its the tq they derived from knowing whp and rpm. since the power was what is actually being used to mvoe the car, the derived tq at the crank is given a "wheel" notation reflecting this. since we also agree that the "effective" tq is roughly 16 times higher at the tire than at the crank (4:1 for first 4:1 for final = 16 overall). so the actual wheel tq in 1st for a stock eg would be around 1,600lbs of tq.
thus why i hate when referring to "wtq" from dyno's. its pointless and just simply confuses people on what it actually means and what you can assume based off of the number
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